Abstract: An ignition coil for internal combustion engine includes: a center core disposed on an inner side of a primary coil and a secondary coil and a side core disposed on an outer side of the primary and secondary coils whose one end face abuts on one end face of the center core and the other end face abuts on the other end face of the center core via a magnet. The side core is formed of a plurality of side core portions obtained by dividing laminated magnetic steel plates at different positions in a longitudinal direction thereof and has a superimposed portion in which the magnetic steel plates of the adjacent side core portions mutually superimpose between the different positions in the longitudinal direction. It thus becomes possible to provide an ignition coil for internal combustion engine capable of suppressing an increase of magnetic circuit resistance markedly without deteriorating assembly workability.

Abstract: An ignition coil device according to the present invention is provided with a primary coil to which a primary current is applied; a secondary coil that is magnetically coupled with the primary coil and generates an ignition voltage when the primary current is cut off, so as to produce a spark discharge between a pair of electrodes of an ignition plug; a noise suppression element electrically connected between the secondary coil and one of the electrodes of the ignition plug; and a case made of an insulating material having a noise suppression element containing unit. The device is characterized by including ribs disposed in the noise suppression element containing unit and arranged in such a way as to face the outer circumferential surface of the noise suppression element and a resin insulating material that is filled into the containing unit and makes contact with the ribs and the noise suppression element.

Abstract: An internal combustion engine ignition coil device according to the present invention is provided with a primary coil to which a primary current is applied; a secondary coil that is magnetically coupled with the primary coil and generates an ignition voltage when the primary current is cut off, so as to produce a spark discharge between a pair of electrodes of an ignition plug; a noise suppression element that is electrically connected between the secondary coil and one of the pair of electrodes of the ignition plug; and a case that is made of an insulating material and has a noise suppression element containing unit for containing the noise suppression element.

Abstract: In an ignition coil device mainly mounted in an internal combustion engine, the installation can be improved even in an ignition coil having a bent leading end.

Abstract: An ignition coil for internal combustion engine includes: a center core disposed on an inner side of a primary coil and a secondary coil and a side core disposed on an outer side of the primary and secondary coils whose one end face abuts on one end face of the center core and the other end face abuts on the other end face of the center core via a magnet. The side core is formed of a plurality of side core portions obtained by dividing laminated magnetic steel plates at different positions in a longitudinal direction thereof and has a superimposed portion in which the magnetic steel plates of the adjacent side core portions mutually superimpose between the different positions in the longitudinal direction. It thus becomes possible to provide an ignition coil for internal combustion engine capable of suppressing an increase of magnetic circuit resistance markedly without deteriorating assembly workability.

Abstract: An ignition coil for an internal combustion engine can increase a contact area between an end of a GND line terminal and a bolt thereby to reduce the contact resistance therebetween. In the ignition coil, a GND potential is ensured by the GND line terminal that is electrically connected at one end thereof to an igniter and at the other end thereof to the internal combustion engine through a bolt inserted into a bolt insertion hole formed in a mounting flange. The GND line terminal is formed at the other end thereof with a bearing surface portion having a hole into which the bolt is inserted. At least part of an inner diameter of the hole in the bearing surface portion is smaller than an inner diameter of the bolt insertion hole.

Abstract: An ignition apparatus for an internal combustion engine is small in size and has high reliability capable of withstanding or enduring a vibration environment of a vehicle to which the ignition apparatus is installed. The ignition apparatus includes a spark plug that has its tip end portion presented in the interior of a cylinder of an internal combustion engine main body, a high voltage generation power supply that serves to apply a high voltage to the spark plug, a microwave oscillation device that has an amplifying element for generating a microwave, and a microwave antenna that is mounted on the spark plug, irradiates the micro wave generated from the microwave oscillation device to the interior of the cylinder, thereby forming a plasma generation region around discharge electrodes of the spark plug. The microwave oscillation device is made into a solid state.

Abstract: An ignition coil apparatus for an internal combustion engine can be produced at low cost with a simple structure, and can be inserted into a bent plug hole without impairing insertability thereof. The apparatus is provided with a high voltage tower (2b) that holds a high voltage terminal (8) in its interior, and a cylindrical plug boot (10) that has electrical insulation and flexibility and is attached at its one end to the high voltage tower (2b). The plug boot 10 is installed on a main body of the internal combustion engine by being inserted into the bent plug hole. The plug boot (10) has a thin wall part (10a) of a thin thickness formed at a location facing in opposition to a bent portion of the plug hole.

Abstract: An ignition apparatus for an internal combustion engine is small in size and has high reliability capable of withstanding or enduring a vibration environment of a vehicle to which the ignition apparatus is installed. The ignition apparatus includes a spark plug that has its tip end portion presented in the interior of a cylinder of an internal combustion engine main body, a high voltage generation power supply that serves to apply a high voltage to the spark plug, a microwave oscillation device that has an amplifying element for generating a microwave, and a microwave antenna that is mounted on the spark plug, irradiates the micro wave generated from the microwave oscillation device to the interior of the cylinder, thereby forming a plasma generation region around discharge electrodes of the spark plug. The microwave oscillation device is made into a solid state.

Abstract: An ignition apparatus for an internal combustion engine can prevent dielectric breakdown resulting from voids, thus making it possible to reduce its size. The apparatus includes a primary bobbin, a primary coil formed of a primary coil conductor wound around the primary bobbin, a secondary bobbin arranged in concentric relation to the primary bobbin, a secondary coil formed of a secondary coil conductor wound around the secondary bobbin, an insulation casing receiving therein the primary bobbin, the primary coil, the secondary bobbin and the secondary coil, and an insulating resin filled into the insulation case. Grooves for guiding the insulating resin between the primary bobbin and the primary coil are formed on an outer peripheral surface of the primary bobbin around which the primary coil conductor having a polygonal cross section is wound.

Abstract: An ignition coil apparatus for an internal combustion engine with a cylinder having first and second spark plugs can reliably detect an ionic current without discharging a bias voltage even at the start of supplying a primary current. The apparatus includes a coil member with primary and secondary coils. The secondary coil has first and second ends connected to the spark plugs through high voltage output terminals, respectively. A first diode has its anode connected to a capacitor, and its cathode connected between the first end of the secondary coil, at which a high positive voltage is generated upon interruption of the primary current, and a high voltage output terminal at a secondary coil first end side. A second diode has its anode connected to the secondary coil first end, and its cathode connected to a junction between the first diode and the high voltage output terminal.

Abstract: An ignition coil apparatus for an internal combustion engine with a cylinder having first and second spark plugs can reliably detect an ionic current without discharging a bias voltage even at the start of supplying a primary current. The apparatus includes a coil member with primary and secondary coils. The secondary coil has first and second ends connected to the spark plugs through high voltage output terminals, respectively. A first diode has its anode connected to a capacitor, and its cathode connected between the first end of the secondary coil, at which a high positive voltage is generated upon interruption of the primary current, and a high voltage output terminal at a secondary coil first end side. A second diode has its anode connected to the secondary coil first end, and its cathode connected to a junction between the first diode and the high voltage output terminal.

Abstract: An ignition coil apparatus for an internal combustion engine can be produced at low cost with a simple structure, and can be inserted into a bent plug hole without impairing insertability thereof. The apparatus is provided with a high voltage tower (2b) that holds a high voltage terminal (8) in its interior, and a cylindrical plug boot (10) that has electrical insulation and flexibility and is attached at its one end to the high voltage tower (2b). The plug boot 10 is installed on a main body of the internal combustion engine by being inserted into the bent plug hole. The plug boot (10) has a thin wall part (10a) of a thin thickness formed at a location facing in opposition to a bent portion of the plug hole.

Abstract: An ignition apparatus for an internal combustion engine can prevent dielectric breakdown resulting from voids, thus making it possible to reduce its size. The apparatus includes a primary bobbin, a primary coil formed of a primary coil conductor wound around the primary bobbin, a secondary bobbin arranged in concentric relation to the primary bobbin, a secondary coil formed of a secondary coil conductor wound around the secondary bobbin, an insulation casing receiving therein the primary bobbin, the primary coil, the secondary bobbin and the secondary coil, and an insulating resin filled into the insulation case. Grooves for guiding the insulating resin between the primary bobbin and the primary coil are formed on an outer peripheral surface of the primary bobbin around which the primary coil conductor having a polygonal cross section is wound.

Abstract: An ignition coil for an internal combustion engine can increase a contact area between an end of a GND line terminal and a bolt thereby to reduce the contact resistance therebetween. In the ignition coil, a GND potential is ensured by the GND line terminal that is electrically connected at one end thereof to an igniter and at the other end thereof to the internal combustion engine through a bolt inserted into a bolt insertion hole formed in a mounting flange. The GND line terminal is formed at the other end thereof with a bearing surface portion having a hole into which the bolt is inserted. At least part of an inner diameter of the hole in the bearing surface portion is smaller than an inner diameter of the bolt insertion hole.